[Qemu-devel] [PATCH v13 06/17] qmp: Add block-dirty-bitmap-enable and block-dirty-bitmap-disable

[John Snow <jsnow@redhat.com>]

This allows to put the dirty bitmap into a disabled state where it is
read only. A disabled bitmap will ignore any attempts to set or reset
any of its bits, but can otherwise be renamed, deleted, or re-enabled.

It will be used before backup or writing to persistent file.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
 block.c               | 25 +++++++++++++++++++++++++
 blockdev.c            | 40 ++++++++++++++++++++++++++++++++++++++++
 include/block/block.h |  3 +++
 qapi/block-core.json  | 28 ++++++++++++++++++++++++++++
 qmp-commands.hx       | 10 ++++++++++
 5 files changed, 106 insertions(+)

diff --git a/block.c b/block.c
index 8b40e38..1fa2ed5 100644
--- a/block.c
+++ b/block.c
@@ -54,6 +54,7 @@
 struct BdrvDirtyBitmap {
     HBitmap *bitmap;
     char *name;
+    bool disabled;
     QLIST_ENTRY(BdrvDirtyBitmap) list;
 };
 
@@ -5412,10 +5413,16 @@ BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs,
     bitmap = g_new0(BdrvDirtyBitmap, 1);
     bitmap->bitmap = hbitmap_alloc(bitmap_size, ffs(sector_granularity) - 1);
     bitmap->name = g_strdup(name);
+    bitmap->disabled = false;
     QLIST_INSERT_HEAD(&bs->dirty_bitmaps, bitmap, list);
     return bitmap;
 }
 
+bool bdrv_dirty_bitmap_enabled(BdrvDirtyBitmap *bitmap)
+{
+    return !bitmap->disabled;
+}
+
 void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap)
 {
     BdrvDirtyBitmap *bm, *next;
@@ -5430,6 +5437,16 @@ void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap)
     }
 }
 
+void bdrv_disable_dirty_bitmap(BdrvDirtyBitmap *bitmap)
+{
+    bitmap->disabled = true;
+}
+
+void bdrv_enable_dirty_bitmap(BdrvDirtyBitmap *bitmap)
+{
+    bitmap->disabled = false;
+}
+
 BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs)
 {
     BdrvDirtyBitmap *bm;
@@ -5494,12 +5511,14 @@ void bdrv_dirty_iter_init(BlockDriverState *bs,
 void bdrv_set_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
                            int64_t cur_sector, int nr_sectors)
 {
+    assert(bdrv_dirty_bitmap_enabled(bitmap));
     hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
 }
 
 void bdrv_reset_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
                              int64_t cur_sector, int nr_sectors)
 {
+    assert(bdrv_dirty_bitmap_enabled(bitmap));
     hbitmap_reset(bitmap->bitmap, cur_sector, nr_sectors);
 }
 
@@ -5508,6 +5527,9 @@ static void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector,
 {
     BdrvDirtyBitmap *bitmap;
     QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
+        if (!bdrv_dirty_bitmap_enabled(bitmap)) {
+            continue;
+        }
         hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
     }
 }
@@ -5517,6 +5539,9 @@ static void bdrv_reset_dirty(BlockDriverState *bs, int64_t cur_sector,
 {
     BdrvDirtyBitmap *bitmap;
     QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
+        if (!bdrv_dirty_bitmap_enabled(bitmap)) {
+            continue;
+        }
         hbitmap_reset(bitmap->bitmap, cur_sector, nr_sectors);
     }
 }
diff --git a/blockdev.c b/blockdev.c
index 8842e39..d3599ac 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2053,6 +2053,46 @@ void qmp_block_dirty_bitmap_remove(const char *node, const char *name,
     aio_context_release(aio_context);
 }
 
+void qmp_block_dirty_bitmap_enable(const char *node, const char *name,
+                                   Error **errp)
+{
+    AioContext *aio_context;
+    BdrvDirtyBitmap *bitmap;
+    BlockDriverState *bs;
+
+    bitmap = block_dirty_bitmap_lookup(node, name, &bs, errp);
+    if (!bitmap) {
+        return;
+    }
+
+    aio_context = bdrv_get_aio_context(bs);
+    aio_context_acquire(aio_context);
+
+    bdrv_enable_dirty_bitmap(bitmap);
+
+    aio_context_release(aio_context);
+}
+
+void qmp_block_dirty_bitmap_disable(const char *node, const char *name,
+                                    Error **errp)
+{
+    AioContext *aio_context;
+    BdrvDirtyBitmap *bitmap;
+    BlockDriverState *bs;
+
+    bitmap = block_dirty_bitmap_lookup(node, name, &bs, errp);
+    if (!bitmap) {
+        return;
+    }
+
+    aio_context = bdrv_get_aio_context(bs);
+    aio_context_acquire(aio_context);
+
+    bdrv_disable_dirty_bitmap(bitmap);
+
+    aio_context_release(aio_context);
+}
+
 int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data)
 {
     const char *id = qdict_get_str(qdict, "id");
diff --git a/include/block/block.h b/include/block/block.h
index 41b8418..ae7e2ab 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -446,9 +446,12 @@ BdrvDirtyBitmap *bdrv_find_dirty_bitmap(BlockDriverState *bs,
                                         const char *name);
 void bdrv_dirty_bitmap_make_anon(BlockDriverState *bs, BdrvDirtyBitmap *bitmap);
 void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap);
+void bdrv_disable_dirty_bitmap(BdrvDirtyBitmap *bitmap);
+void bdrv_enable_dirty_bitmap(BdrvDirtyBitmap *bitmap);
 BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs);
 uint32_t bdrv_get_default_bitmap_granularity(BlockDriverState *bs);
 uint32_t bdrv_dirty_bitmap_granularity(BdrvDirtyBitmap *bitmap);
+bool bdrv_dirty_bitmap_enabled(BdrvDirtyBitmap *bitmap);
 int bdrv_get_dirty(BlockDriverState *bs, BdrvDirtyBitmap *bitmap, int64_t sector);
 void bdrv_set_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
                            int64_t cur_sector, int nr_sectors);
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 764719d..a82f8fa 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -1014,6 +1014,34 @@
   'data': 'BlockDirtyBitmap' }
 
 ##
+# @block-dirty-bitmap-enable
+#
+# Enable a dirty bitmap on the device
+#
+# Returns: nothing on success
+#          If @node is not a valid block device, DeviceNotFound
+#          If @name is not found, GenericError with an explanation
+#
+# Since 2.3
+##
+{ 'command': 'block-dirty-bitmap-enable',
+  'data': 'BlockDirtyBitmap' }
+
+##
+# @block-dirty-bitmap-disable
+#
+# Disable a dirty bitmap on the device
+#
+# Returns: nothing on success
+#          If @node is not a valid block device, DeviceNotFound
+#          If @name is not found, GenericError with an explanation
+#
+# Since 2.3
+##
+{ 'command': 'block-dirty-bitmap-disable',
+  'data': 'BlockDirtyBitmap' }
+
+##
 # @block_set_io_throttle:
 #
 # Change I/O throttle limits for a block drive.
diff --git a/qmp-commands.hx b/qmp-commands.hx
index 881a810..ce7782f 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -1253,6 +1253,16 @@ EQMP
         .args_type  = "node:B,name:s",
         .mhandler.cmd_new = qmp_marshal_input_block_dirty_bitmap_remove,
     },
+    {
+        .name       = "block-dirty-bitmap-enable",
+        .args_type  = "node:B,name:s",
+        .mhandler.cmd_new = qmp_marshal_input_block_dirty_bitmap_enable,
+    },
+    {
+        .name       = "block-dirty-bitmap-disable",
+        .args_type  = "node:B,name:s",
+        .mhandler.cmd_new = qmp_marshal_input_block_dirty_bitmap_disable,
+    },
 
 SQMP
 
-- 
1.9.3